The present invention relates generally to communication, and more specifically to a hands-free voice communication apparatus.
Hands-free voice communication devices are commonly used for various applications such as speakerphone, earpiece/headset, hands-free car kit, teleconferencing system, cellular phone, hands-free voice recognition device, and so on. A speakerphone device allows a near-end user to speak into one or more microphones placed at some distance away from the near-end user and to listen to sound from a far-end user via a loudspeaker also placed away from the near-end user. An earpiece/headset device allows a user to communicate with privacy and with hands-free operation. In general, hands-free devices are convenient and comfortable to use and are also safer to use than hands-on or handheld devices in certain situations, e.g., when driving a car or when the user's hands are busy.
A hands-free device typically supports hands-free voice communication with a loudspeaker/receiver and one or more microphones. When the hands-free device is small in size, the close proximity of the loudspeaker to the microphones may cause some major problems. For example, when a speech signal from a far-end user is outputted from the loudspeaker, a portion of this speech signal may be reflected back to the microphones and transmitted back to the far-end user. This acoustic disturbance is referred to as echo and is annoying to the far-end user. In certain instances, the hands-free device may cause acoustic shock or howling due to instability resulting from the microphones picking up reflections of the acoustic signal emitted by the loudspeaker.
Hands-free devices are described in various literatures including U.S. Patent Application Serial Nos. 2003/0157973 and 2004/0033820. Application Serial No. 2003/0157973 describes installing an earpiece inside a cellular phone and using a switch to select between the cellular phone and the earpiece. Application Serial No. 2003/0157973 does not describe a speakerphone feature for the cellular phone. Application Serial No. 2004/0033820 describes a handset that communicates via infrared with a hands-free kit having an earpiece. Application Serial No. 2004/0033820 does not address the integration of a speakerphone.
As can be seen, a hands-free voice communication device that can effectively provide hands-free communication is highly desirable.